While working with re:3D’s in-house Open Gigabot (OGB), I noticed that the right Y limit switch wasn’t very secure. The printed Y limit switch mount was old, a little warped, thin, and was only held on with one screw which allowed it to rotate slightly when the extruder homes. So, I decided to give it an upgrade to make it a little stronger and more secure.
OGB's old Y limit switch mount
I made the new Y limit switch mount thicker and added a second hole so that it can be secured to the printer using two M5x12 screws with M5 washers. (fender washers are recommended, but regular washers work just fine too!)
OGB’s new Y limit switch mount
To install the new Y limit switch mount, the first thing you should do is home XY. Once XY is homed, measure the Y location of the bridge rail in relation to a different part of the printer. I measured from the bridge rail to the front upright hood rail. You could also measure from the bridge rail to the end of the linear rail or to the front of the printer. On the re:3D in-house OGB, this measures at almost exactly 6 inches, but we have made some changes to our in-house printer so it's best to measure where your printer normally homes and double check that the extruder and bridge rail aren’t running into any other part of the printer. Once you’ve measured where your printer normally homes, write it down so you don’t forget it.
Measuring the re:3D in house OGB
Before removing the old Y limit switch mount, turn off your printer and unplug the Y limit switch. You can now remove the old limit switch mount from the printer and then remove the limit switch from the printed mount. You can reuse the same screws and nuts to attach the limit switch to the new limit switch mount. Before installing the new Y limit switch mount, double check that you attached the limit switch to the mount in the correct orientation.
Orientation of the limit switch on the Y limit switch mount
Using 2 M5x12 screws, 2 M5 fender washers, and 2 M5 T-nuts, attach the new Y limit switch mount to the printer, but don’t tighten down the Y limit switch mount onto the rail yet. Once the Y limit switch mount is loosely attached to the printer, move the bridge rail to where it should be when homing (remember the measurement you took earlier!). Move the limit switch mount so that the limit switch is pressing against the bridge rail, and then tighten the screws on the Y limit switch mount to keep it in place.
Attaching the new Y limit switch mount
After the new Y limit switch mount is tightened down, reattach the limit switch wires and turn the printer on. Home XY to double check that the limit switch works. If it doesn’t work, check that the limit switch wires are fully connected to the limit switch. After homing XY, also check to make sure that there is no interference between the extruder and any other part of the printer. If there is any interference, adjust the location of the Y limit switch mount.
Fully assembled and installed Y limit switch mount
As with many of our printed parts, it is recommended that the Y limit switch mount is printed in Polycarbonate to give the mount the strength it needs. The STL file for the new Y limit switch mount can be found on re:3D’s sketchfab account (link), or contact us at email@example.com to order the printed parts. If you have any problems with installing the new mount or getting the limit switch to work, contact us at firstname.lastname@example.org.